The invention relates to a method for obtaining non-magnetic ores from a suspension containing ore particle-magnetic particle agglomerates.
The use of flotation cells for obtaining ores from ore-containing bulk material is well known. An ore-containing pulp, i.e. essentially a suspension of water, ground rock (gangue) and ground ore is fed to a flotation cell or a flotation reactor.
In the context of “magnetic flotation” methods, the pulp is loaded (in a “load process”) with magnetic particles, including, for example, magnetic particles in the form of magnetite, to form ore particle-magnetic particle agglomerates. In order to form the ore particle-magnetic particle agglomerates, prior hydrophobization both of the ore particles and of the magnetic particles is usually required. The formation of the ore particle-magnetic particle agglomerates thus produced essentially by hydrophobic interactions or by attractive forces is achieved by mixing the starting materials, taking account of particular mixing parameters such as shear forces, time, temperature, etc.
Separation of the ore particle-magnetic particle agglomerates from the pulp is carried out by a (first) separating device typically in the form of, or including, a magnetic separator, wherein the magnetic ore particle-magnetic particle agglomerates are extracted from the pulp and are transferred to a concentrate stream which essentially contains the ore particle-magnetic particle agglomerates, small quantities of gangue material and water.
Subsequently, the ore particle-magnetic particle agglomerates are split into the component parts thereof, specifically ore particles and magnetic particles, so that said materials are present together but unbound, in the form of a mixture (in an “unload process”). Typically, the separation of the ore particle-magnetic particle agglomerates is carried out by a further or second separating device with chemical processes with the use of suitable chemicals such as solvents or the like.
The subsequent separation of the magnetic particles which are present essentially in isolation, from the ore particles and the other components of the concentrate stream is also carried out in the context of the “unload” process using a further, or third, separating device, again typically in the form of, or comprising, a magnetic separator in which the magnetic particles are magnetically separated out. Thereafter, separation takes place into a first mass flow containing magnetic particles and a second mass flow containing ore particles, which are present separately from one another and essentially or ideally contain only the respective pure material, that is, either pure magnetic particles or pure ore particles.
A method of this type is disclosed by EP 2 090 367 A1, which relates to a method for the continuous recovery of non-magnetic ores from a pulp containing non-magnetic ore particles. In said process, magnetic or magnetizable magnetic particles are fed to a pulp continuously flowing through a reactor, said magnetic particles forming ore particle-magnetic particle agglomerates with the non-magnetic ore particles. The ore particle-magnetic particle agglomerates are moved by a magnetic field into an accumulator region of the reactor and are conducted out of the accumulator region of the reactor.
In the known methods, it is often problematic that the first mass flow containing magnetic particles still contains a certain content of ore particles and the second mass flow containing ore particles still contains a certain content of magnetic particles. Therefore, certain losses occur in relation both to the magnetic particles and the ore particles, because both the ore particles present in the first mass flow and the magnetic particles present in the second mass flow are not available, or only with significant effort, for further processing, negatively affecting the process yield. Detection of the composition of the first or second mass flow does not take place.